1. Technical Field of the Invention
The present invention relates to cosmetic and/or dermatological compositions intended for artificially coloring the skin, characterized in that they comprise, in a cosmetically acceptable vehicle, at least one sorghum extract; the said compositions not containing a flavylium salt which is unsubstituted in position 3 and which is substituted with at least one hydroxyl or alkoxy radical.
The invention also relates to its uses for the manufacture of cosmetic or dermatological compositions for coloring the skin.
2. Description of the Prior Art
Nowadays, it is important to look healthy and a tanned skin is always a sign of good health. However, a natural tan is not always desirable since it requires prolonged exposure to UV radiation, in particular to UV-A radiation which causes the tanning of the skin but, however, is liable to induce an adverse change therein, in particular in the case of sensitive skin or of skin which is continually exposed to solar radiation. It is thus desirable to find an alternative to a natural tan which is compatible with the requirements of such skin types.
Most of the cosmetic products intended for artificially tanning the skin are based on carbonyl derivatives which, by interacting with the amino acids in the skin, allow the formation of colored products.
To this end, it is known that dihydroxy-acetone, or DHA, is a particularly advantageous product which is commonly used in cosmetics as an agent for artificially tanning the skin; when applied to the skin, in particular to the face, it gives a tanning or bronzing effect which is similar in appearance to that which may result from prolonged exposure to sunlight (a natural tan) or under a UV lamp.
A drawback of DHA is the length of time the coloration takes to develop: specifically, several hours (3 to 5 hours in general) are required for the coloration to be revealed. There is thus an increasing demand for fast-acting self-tanning products which give a coloration closer to that of a natural tan.
Thus, efforts are continually being made to find novel compounds and novel compositions which can give the skin an artificial coloration close to that of a natural tan in a simple, effective, fast and risk-free manner.
Sorghum extracts have been known for a long time as food colorants. They give a reddish brown color and have in their composition flavonoids, anthocyanidins and tannins.
Now, after considerable research conducted in the field of artificial coloring of the skin, the Applicant has discovered that the use as skin-coloring agent of at least one sorghum extract, in the absence of a flavylium salt which is unsubstituted in position 3 and which is substituted with at least one hydroxyl or alkoxy radical, makes it possible to give the skin, immediately after applying the product to it, an artificial coloration close to that of a natural tan.
The subject of the present invention is therefore a novel cosmetic and/or dermatological composition, intended for artificially coloring the skin close to a natural tan, characterized in that it comprises, in a cosmetically acceptable vehicle, at least one sorghum extract; the said composition not containing a flavylium salt which is unsubstituted in position 3 and which is substituted with at least one hydroxyl or alkoxy radical.
A subject of the present invention is also the novel use of at least one sorghum extract in a cosmetic composition not containing a flavylium salt which is unsubstituted in position 3 and which is substituted with at least one hydroxyl or alkoxy radical, with the aim of giving the skin an artificial coloration close to that of a natural tan.
A subject of the present invention is also a process for giving the skin an artificial coloration close to that of a natural tan, characterized in that it consists in applying to the skin an effective amount of a cosmetic composition as defined above.
The compositions and uses in accordance with the invention make it possible to obtain an artificial coloration close to that of a natural tan in a short space of time. Thus, an immediate coloration is obtained, which allows the application to be visualized and consequently allows more uniform spreading of the composition on the skin and thus of the resulting coloration. Moreover, the artificial coloration obtained on the skin according to the invention is extremely close to that of a natural tan.
For the purposes of the present invention, the expression xe2x80x9ccomposition intended for artificially coloring the skinxe2x80x9d will be understood to mean a formulation with a particular affinity for the skin which allows it to give the skin a long-lasting coloration, which is non-covering (that is to say which does not have a tendency to opacify the skin) and which is not removed either with water or with a solvent, and which withstands both rubbing and washing with a solution containing surfactants. Such a long-lasting coloration is thus distinguished from the superficial and transient coloration provided, for example, by a make-up product.
Other characteristics, aspects and advantages of the present invention will become apparent on reading the detailed description which follows.
The compositions in accordance with the present invention make it possible to obtain, 30 minutes after application to a fair skin at a rate of 2 mg/cm2, a darkening characterized in the (L*, a*, b*) calorimetric measuring system by a xcex94L* ranging from xe2x88x920.5 to xe2x88x9220. Preferably, xcex94L* will range from xe2x88x920.5 to xe2x88x9215.
The compositions in accordance with the present invention give, 30 minutes after application to a fair skin at a rate of 2 mg/cm2, a coloration defined in the (L*, a*, b*) calorimetric measuring system by a ratio xcex94a*/xcex94b* ranging from 0.5 to 3 and even more particularly ranging from 0.8 to 2.
According to the present invention, the term xe2x80x9cfair skinxe2x80x9d means an untanned skin whose calorimetric characteristics may be defined by its ITA angle as defined in the publication by A. Chardon et al., xe2x80x9cSkin Color Typology and Suntanning Pathwaysxe2x80x9d presented at the 16th IFSCC congress, Oct. 8-10, 1990, New York, and in Int. J. Cosm. Sci. 13 191-208 (1991). The fair skins as defined in this classification have an ITA angle of between 35 and 55.
In the (L*, a*, b*) calorimetric measuring system:
L* represents the luminance or clarity, a* represents the red-green axis (xe2x88x92a*=green, +a*=red) and b* represents the yellow-blue axis (xe2x88x92b*=blue, +b*=yellow). Thus, a* and b* express the shade of the skin.
xcex94L* reflects the darkening of the color: the more negative the xcex94L*, the darker the color, with:
xcex94L*=L* uncolored skinxe2x88x92L* colored skin. 
The ratio xcex94a*/xcex94b* reflects the red/yellow balance and thus the shade, with:
xcex94a*=a* uncolored skinxe2x88x92a* colored skin 
xcex94b*=b* uncolored skinxe2x88x92b* colored skin. 
The sorghum extracts in accordance with the invention are obtained from the whole plant, the stems, the seeds or the leaves of the genus Sorghum. The preferred species of sorghum are chosen from Sorghum bicolor, Sorghum caudatum, Sorghum nervosum, Sorghum durra, Sorghum vulgare and the Sorghum species in association with Colletotrichum graminicola. 
The sorghum extracts in accordance with the invention are more particularly the extracts of Sorghum vulgare such as the commercial product Sorghum Extract Absorbance greater than 30 sold by Premier Specialties.
The sorghum extracts in accordance with the invention are obtained from the extraction of the whole plant or of the plant parts cited above which may be in the fresh state or in the dry state.
The sorghum extract in accordance with the invention may be obtained by a process comprising the following steps:
(a) an extraction of the whole plant, the stems, the seeds or the leaves of the genus Sorghum in an aqueous medium which may also contain at least one organic solvent;
(b) a maceration in an alkaline medium having a pH on the order of 11-12;
(c) optionally a precipitation from the maceration medium by addition of an acid so as to reach a pH on the order of 1-2.
The extraction may be carried out in an acidic medium as described in the Chinese patents CN 1035512 C and CN 1064284A and in the publication by M KOUDA-BONAFOS, E CZYZEWSKA, M NACRO and A C OEHLSCHLAGER. xe2x80x9cIsolation of apigenin from leaf sheets of Sorghum caudatumxe2x80x9d Journal of Chemical Ecology, Vol. 20, No. 8, p. 2123-2125 (1995).
It may also be carried out in an alkaline medium followed by precipitation in an acidic medium as described in the Chinese patent CN 1065079A and in the publication by J P REY, J L POUSSET, J LEVESQUE and P WANTY. xe2x80x9cIsolation and composition of a natural dye from the stems of sorghum bicolor (L.) Moench subsp. Americanum caudatumxe2x80x9d Cereal Chem. Vol. 70(6), p. 759-760 (1993).
The extraction may also be carried out in an organic medium as described in the publications by J WANG xe2x80x9cStudies on extraction of pigment from sorghum husks and its propertiesxe2x80x9d Huaxue Shijie, Vol. 39 (4), p. 211-213 (1998) and by A SEREME, M KOUDA-BONAFOS and M NACRO xe2x80x9cPhenolic compounds in Sorghum caudatum tissues during plant developmentxe2x80x9d Biomass and Bioenergy Vol. 4(1), p. 69-71 (1993).
The organic solvents used for the extraction may be alcohols such as ethanol, methanol, normal primary propyl alcohol, isopropyl alcohol, normal primary butyl alcohol, propylene glycol and glycerol for example. The organic solvents may also be represented by diethyl ether, acetone, ethyl methyl ketone, ethyl acetate for example. The organic solvents used may also be supercritical fluids or fluorinated solvents such as dodecafluoropentane, tetradecafluorohexane, perfluorinated N-methylmorpholine and methoxynonafluorobutane for example.
Step (b) of maceration in an alkaline medium may be carried out for a period of 15-25 days at a temperature of 60-80xc2x0 C. in a 0.1N sodium hydroxide solution having a pH on the order of 11-12.
Step (c) of precipitation by addition of acid may be carried out, for example, with ION hydrochloric acid so as to reach a pH on the order of 1-2. The aqueous suspension thus obtained is then filtered in order to recover the precipitate which is then dried.
Steps (b) and (c) may be repeated several times.
The concentration of sorghum extract in accordance with the invention preferably varies from 0.0001% to 10%, and still more preferably from 0.001% to 5% by weight, relative to the total weight of the composition.
According to a particular form, the compositions according to the invention may additionally contain mono- or polycarbonyl-containing self-tanning agents.
The mono- or polycarbonyl-containing self-tanning agents are chosen, for example, from isatin, alloxan, ninhydrin, glyceraldehyde, mesotartaric aldehyde, glutaraldehyde, erythrulose, pyrazoline-4,5-dione derivatives as described in patent application FR-2,466,492 and WO 97/35842, dihydroxyacetone (DHA), 4,4-dihydroxypyrazoline-5-one derivatives as described in patent application EP-903,342, it being possible for these self-tanning agents to be combined or otherwise with direct dyes or indole derivatives.
In a preferred embodiment of the invention, dihydroxyacetone (DHA) will be more particularly used.
The mono- or polycarbonyl-containing self-tanning agents are generally present in the compositions according to the invention in proportions ranging from 0.1% to 10% by weight relative to the total weight of the composition, and preferably from 0.2% to 8% by weight relative to the total weight of the composition.
According to a particular form, the compositions of the invention may additionally contain one or more ultraviolet radiation screening agents.
The ultraviolet radiation screening agents may be chosen from organic UV screening agents or inorganic UV radiation screening agents.
The organic UV screening agents in accordance with the invention may be water-soluble, fat-soluble or insoluble in the customary cosmetic solvents. They are chosen in particular from anthranilates; cinnamic derivatives; dibenzoylmethane derivatives; salicylic derivatives; camphor derivatives; triazine derivatives such as those disclosed in patent applications U.S. Pat. No. 4,367,390, EP-863,145, EP-517,104, EP-570,838, EP-796,851, EP-775,698, EP-878,469 and EP-933,376; benzophenone derivatives in particular those described in applications EP-A-1,046,391 and DE-10,012,408; benzalmalonate derivatives; xcex2,xcex2xe2x80x2-diphenylacrylate derivatives; benzotriazole derivatives; benzimidazole derivatives; imidazolines; bis-benzoazolyl derivatives such as those disclosed in patents EP-669,323 and U.S. Pat. No. 2,463,264; p-aminobenzoic acid (PABA) derivatives; methylenebis(hydroxyphenylbenzotriazole) derivatives as disclosed in patent applications U.S. Pat. Nos. 5,237,071, 5,166,355, GB-2,303,549, DE-19,726,184 and EP-893,119; screening polymers and screening silicones such as those disclosed in particular in patent application WO 93/04665; dimers derived from xcex1-alkylstyrene, such as those disclosed in patent application DE-19,855,649; 4,4-diarylbutadiene derivatives such as those disclosed in patent applications EP-0,967,200, DE-19,755,649, EP-1,333,981 and mixtures thereof.
As examples of organic screening agents, mention may be made of those indicated below under their INCI name:
Para-Aminobenzoic Acid Derivatives:
PABA,
Ethyl PABA,
Ethyl Dihydroxypropyl PABA,
Ethylhexyl Dimethyl PABA sold in particular under the trademark xe2x80x9cEscalol 507xe2x80x9d by ISP,
Glyceryl PABA,
PEG-25 PABA sold under the trademark xe2x80x9cUvinul P25xe2x80x9d by BASF,
Salicylic Derivatives:
Homosalate sold under the trademark xe2x80x9cEusolex HMSxe2x80x9d by RONA/EM Industries,
Ethylhexyl Salicylate sold under the trademark xe2x80x9cNeo Heliopan OSxe2x80x9d by Haarmann and Reimer,
Dipropyleneglycol Salicylate sold under the trademark xe2x80x9cDipsalxe2x80x9d by Scher,
TEA Salicylate, sold under the name xe2x80x9cNeo Heliopan TSxe2x80x9d by Haarmann and Reimer,
Dibenzoylmethane Derivatives:
Butyl Methoxydibenzoylmethane sold in particular under the trademark xe2x80x9cParsol 1789xe2x80x9d by Hoffmann La Roche,
Isopropyl Dibenzoylmethane,
Cinnamic Derivatives:
Ethylhexyl Methoxycinnamate sold in particular under the trademark xe2x80x9cParsol MCXxe2x80x9d by Hoffmann La Roche,
Isopropyl Methoxycinnamate,
Isoamyl Methoxycinnamate sold under the trademark xe2x80x9cNeo Heliopan E 1000xe2x80x9d by Haarmann and Reimer,
Cinoxate,
DEA Methoxycinnamate,
Diisopropyl Methylcinnamate,
Glyceryl Ethylhexanoate Dimethoxycinnamate
xcex2,xcex2xe2x80x2-Diphenylacrylate Derivatives:
Octocrylene sold in particular under the trademark xe2x80x9cUvinul N539xe2x80x9d by BASF,
Etocrylene, sold in particular under the trademark xe2x80x9cUvinul N35xe2x80x9d by BASF,
Benzophenone Derivatives:
Benzophenone-1 sold under the trademark xe2x80x9cUvinul 400xe2x80x9d by BASF,
Benzophenone-2 sold under the trademark xe2x80x9cUvinul D50xe2x80x9d by BASF,
Benzophenone-3 or Oxybenzone, sold under the trademark xe2x80x9cUvinul M40xe2x80x9d by BASF,
Benzophenone-4 sold under the trademark xe2x80x9cUvinul MS40xe2x80x9d by BASF,
Benzophenone-5,
Benzophenone-6 sold under the trademark xe2x80x9cHelisorb 11xe2x80x9d by Norquay,
Benzophenone-8 sold under the trademark xe2x80x9cSpectra-Sorb UV-24xe2x80x9d by American Cyanamid,
Benzophenone-9 sold under the trademark xe2x80x9cUvinul DS-49xe2x80x9d by BASF,
Benzophenone-12
Benzylidenecamphor Derivatives:
3-Benzylidenecamphor manufactured under the trademark xe2x80x9cMexoryl SDxe2x80x9d by Chimex,
4-Methylbenzylidenecamphor sold under the trademark xe2x80x9cEusolex 6300xe2x80x9d by Merck,
Benzylidenecamphor Sulfonic Acid manufactured under the trademark xe2x80x9cMexoryl SLxe2x80x9d by Chimex,
Camphor Benzalkonium Methosulfate manufactured under the trademark xe2x80x9cMexoryl SOxe2x80x9d by Chimex,
Terephthalylidene Dicamphor Sulfonic Acid manufactured under the trademark xe2x80x9cMexoryl SXxe2x80x9d by Chimex,
Polyacrylamidomethyl Benzylidene Camphor manufactured under the trademark xe2x80x9cMexoryl SWxe2x80x9d by Chimex,
Phenylbenzimidazole Derivatives:
Phenylbenzimidazole Sulfonic Acid sold in particular under the trademark xe2x80x9cEusolex 232xe2x80x9d by Merck,
Benzimidazilate sold under the trademark xe2x80x9cNeo Heliopan APxe2x80x9d by Haarmann and Reimer,
Triazine Derivatives:
Anisotriazine sold under the trademark xe2x80x9cTinosorb Sxe2x80x9d by Ciba Geigy,
Ethylhexyl Triazone sold in particular under the trademark xe2x80x9cUvinul T150xe2x80x9d by BASF,
Diethylhexyl Butamido Triazone sold under the trademark xe2x80x9cUvasorb HEBxe2x80x9d by Sigma 3V,
2,4,6-Tris(diisobutyl 4xe2x80x2-aminobenzalmalonate)-s-triazine,
Phenylbenzotriazole Derivatives:
Drometrizole Trisiloxane sold under the name xe2x80x9cSilatrizolexe2x80x9d by Rhodia Chimie,
Methylene bis-Benzotriazolyl Tetramethylbutylphenol, sold in solid form under the trademark xe2x80x9cMixxim BB/100xe2x80x9d by Fairmount Chemical or in micronized form as an aqueous dispersion under the trademark xe2x80x9cTinosorb Mxe2x80x9d by Ciba Specialty Chemicals,
Anthranilic Derivatives:
Menthyl anthranilate sold under the trademark xe2x80x9cNeo Heliopan MAxe2x80x9d by Haarmann and Reimer,
Imidazoline Derivatives:
Ethylhexyl Dimethoxybenzylidene Dioxoimidazoline Propionate,
Benzalmalonate Derivatives:
Polyorganosiloxane containing benzalmalonate functional groups sold under the trademark xe2x80x9cParsol SLXxe2x80x9d by Hoffmann La Roche
4,4-Diarylbutadiene Derivatives:
1,1-Dicarboxy(2,2xe2x80x2-dimethylpropyl)-4,4-diphenyl-butadiene and mixtures thereof.
The organic UV screening agents most particularly preferred are chosen from the following compounds:
Ethylhexyl Salicylate,
Butyl Methoxydibenzoylmethane,
Ethylhexyl Methoxycinnamate,
Octocrylene,
Phenylbenzimidazole Sulfonic Acid,
Terephthalylidene Dicamphor Sulfonic,
Benzophenone-3,
Benzophenone-4,
Benzophenone-5,
4-Methylbenzylidene Camphor,
Benzimidazilate,
Anisotriazine,
Ethylhexyl Triazone,
Diethylhexyl Butamide Triazone,
Methylene bis-Benzotriazolyl Tetramethylbutylphenol, 1,1-Dicarboxy(2,2xe2x80x2-dimethyl-propyl)-4,4-diphenyl-butadiene
Drometrizole Trisiloxane, and mixtures thereof.
The inorganic screening agents are generally pigments or alternatively nanopigments (average size of the primary particles: generally between 5 nm and 100 nm and preferably between 10 nm and 50 nm) of metal oxides which are coated or uncoated, such as, for example, nanopigments of titanium oxide (amorphous or crystallized in rutile and/or anatase form), of iron oxide, of zinc oxide, of zirconium oxide or of cerium oxide, which are all UV stabilizers that are well known per se. Conventional coating agents are, moreover, alumina and/or aluminum stearate. Such coated or uncoated metal oxide nanopigments are disclosed in particular in patent applications EP-A-0,518,772 and EP-A-0,518,773.
The radiation screening agents in accordance with the invention are generally present in the compositions according to the invention in proportions ranging from 0.1% to 20% by weight relative to the total weight of the composition, and preferably ranging from 0.2% to 15% by weight relative to the total weight of the composition.
The compositions in accordance with the present invention may also comprise conventional cosmetic adjuvants chosen in particular from fatty substances, organic solvents, ionic or nonionic thickeners, softeners, antioxidants, anti-free-radical agents, opacifiers, stabilizers, emollients, silicones, xcex1-hydroxy acids, insect repellents, antifoams, moisturizers, vitamins, fragrances, preserving agents, surfactants, fillers, polymers, propellants, basifying or acidifying agents, coloring agents, or any other ingredient usually used in the cosmetic or dermatological field, in particular for manufacturing antisun compositions in the form of emulsions.
The fatty substances may consist of an oil or a wax or mixtures thereof. The expression wax is understood to mean a compound which is solid or substantially solid at room temperature, and whose melting point is generally greater than 35xc2x0 C.
As oils, mention may be made of mineral oils (paraffin); vegetable oils (sweet almond, macadamia, blackcurrant seed or jojoba oil); synthetic oils such as perhydrosqualene, alcohols, fatty acids or esters (such as benzoate of C12-C15 alcohols which is sold under the trademark xe2x80x9cFinsolv TNxe2x80x9d by Finetex, octyl palmitate, isopropyl lanolate, triglycerides including those of capric/caprylic acids), oxyethylenated or oxypropylenated fatty esters and ethers; silicone oils (cyclomethicone, polydimethylsiloxanes, or PDMS) or fluoro oils, polyalkylenes.
As waxy compounds, mention may be made of paraffin, carnauba wax, beeswax, hydrogenated castor oil.
Among the organic solvents, mention may be made of lower alcohols and polyols.
The latter may be chosen from glycols and glycol ethers such as ethylene glycol, propylene glycol butylene glycol, dipropylene glycol or diethylene glycol.
The thickeners may be chosen in particular from crosslinked polyacrylic acids, modified or unmodified guar gums and celluloses such as hydroxypropylated guar gum, methylhydroxyethylcellulose and hydroxypropylmethylcellulose.
Needless to say, a person skilled in the art will take care to select the abovementioned optional additional compound(s) and/or the amounts thereof such that the advantageous properties intrinsically associated with the use of the compounds of the flavylium salt type in accordance with the invention are not, or are not substantially, adversely affected by the addition(s) envisaged.
The compositions according to the invention may be prepared according to techniques well known to a person skilled in the art, in particular those intended for the preparation of emulsions of the oil-in-water or water-in-oil type.
This composition may be provided in particular in the form of a simple or complex emulsion (O/W, W/O, O/W/O or W/O/W) such as a cream, a milk, or in the form of a gel or a cream-gel, in the form of a lotion, a powder, a solid stick and may be optionally packaged as an aerosol and may be provided in the form of a mousse or a spray.
Preferably, the compositions according to the invention are provided in the form of an oil-in-water or water-in-oil emulsion.
When it is an emulsion, the aqueous phase of this emulsion may comprise a nonionic vesicular dispersion prepared according to known processes (Bangham, Standish and Watkins, J. Mol. Biol. 13, 238 (1965), FR-2,315,991 and FR-2,416,008).
Concrete but in no way limiting examples illustrating the invention will now be given.